Arrangement of Electrons in the Atoms
1) The energy levels of electrons are denoted by the numbers 1,2,3,4… and shells are represented by K,L,M,N…..
2) The arrangement of electrons in various energy levels or shells of an atom is known as electronic configuration of the element.
The maximum number of electrons which can be accommodated in any energy level of an atom is given by 2n²(Bohr-Bury Rule).
For Ex: For 1st energy level n=1
Max number of electrons in 1st energy level=2n² =2
For 2nd energy level n=2
Max number of electrons in 2nd energy level= 8
For 3rd energy level n=3
Max number of electrons in 3rd energy level =18
3) Each energy level is associated with a fixed amount of energy, the shell nearest to the nucleus have minimum energy and the shell farthest from the nucleus have maximum energy.
4) Electrons in an atom do not occupy a new shell unless all the inner shells are completely filled with electrons.